Antigravity Heroes

Antigravity Heroes is an exciting good-versus-evil battle between a brother-sister superhero team and the evil Mephisto. It is book #3 in the "Wanted: Superheroes" series.
In previous stories, our heroes, Eddie and Samantha Hertz, faced earthquakes and hypnotized zombie-like people. What could be worse?
Birds. Yes, birds. And lots of them. Eagles, hawks, owls, herons, and more. The villain Mephisto has hypnotized tens of thousands of them to do his evil bidding.
The situation gets even stranger. Our heroes have to battle gravity itself. Mephisto has stolen antigravity belts that allow him to fly. But the belts have a flaw, and he tries to force Eddie to perfect them. In the meantime, Mephisto uses the hypnotized birds to paralyze the city while he steals millions of dollars.
Against all odds, Eddie and Samantha, their mother, their Uncle Milligan, the new Damocles, and the eccentric Dr. Gilbert G. Godwin, work together to battle the hypnotized birds and their controlling master.
As usual, the entire world is in danger, and only the Hertz heroes can save it.